The influence of chemical factors on the selectivity of Pinus resinosa stumps for Fomes annosus

Compounds such as resins or phenols produced by the host in response to wounding or fungal penetration may play an important role as factors of resistance against Fomes annosus. By extracting stem sections, that were kept for different intervals in a closed chamber, with different organic solvents chloroform produced the most inhibitory extractives against F. annosus. This may explain at least partially the decreasing stump selectivity for F. annosus. Three compounds were isolated from the neutral fractions of chloroform extractives from 24 days wounded wood discs which were found to be different from the compounds in normal and 12 days fractions. Spectrophotometric analyses reveal some characteristics of these isolated compounds, whereas their chemical formula and structure need further investigation.     

Some observations on the longevity of Fomes annosus in conifer stumps.

The longevity of Fomes annosus in conifer stumps was assessed in 3 investigations, which showed that the fungus could remain active in stumps for periods of 16 to 62 years.     

Chemical resistance of Pinus densiflora to Fomes annosus

One compound isolated from the stem wood of Pinus densiflora Sieb. Zucc. is responsible for its resistance to Fomes annosus (Fr.) Cke. From thin layer chromatography and microanalytical evidence, the inhibitory compound is nitrogenous and may be an alkaloid.     

Identification of some compounds associated with resistance of Pinus densiflora to Fomes annosus

From the heartwood-free stemwood of Pinus densiflora, 7 compounds inhibitory to the linear growth of Fomes annosus were isolated. These were identified as pinosylvin, pinosylvin monomethyl ether, (3-sitosterol, a cembrol-like diterpene alcohol, and three isomeric diterpene acids belonging to the abietane group, one of which is probably palustric acid. Other antifungal fractions contained complex mixtures and were not characterized.     

The effect of L-threonine on oxalic acid synthesis by Fomes annosus

Addition of 1 mM L-threonine to the growth medium of Fomes annosus inhibited its glyoxylate deliydrogenase activity and the synthesis of oxalic acid. Malate synthetase was synthesized de novo in the presence of L-threonine. Lignosulfonate completely blocked the effect of the amino acid in both glucose or cellobiose-containing medium.     

The mating system of Fomes annosus (Heterobasidion annosum)

Conditions are described which allow reproducible formation of fruiting bodies of Fomes annosus under sterile conditions, suitable for genetic studies. Analysis of the progeny of a fruiting body isolated from woods revealed a bipolar mechanism of genetic control of fruiting body formation as well as “Grenz-haut”-formation.     

Fomes annosus sporocarps - their abundance on decayed logs left in the forest

On logs of Norway spruce, discarded and left lying after thinning because of severe decay by Fomes annosus, numerous sporocarps of F. annosus develop after one to two years. The surface area, position, number, and time of appearance of the fruiting bodies varied between two test areas. Removal of rotted logs is recommended as a prophylactic method of Fomes control in Picea abies stands.     

Factors contributing to the resistance of Pinus densiflora (Sieb. and Zucc.) and susceptibility of Pinus rigida × radiata to Fomes annosus

Water, ethanol, ethyl acetatc and chloroform extractives of Pinus densiflora and P. rigida×radiata were made. The ethanol extractives from P. densiflora were most inhibitory in bioassays using two F. annosus strains. Thcse cxtractives werc scparated into acid, base, and ncutral parts. Fractions were collected from the neutral part and bioassays conducted to determine which contained activc fungitoxic compounds. Thin layer diromatography revealed the number of compounds in each fraction.     

Examination of metabolic products of the fungus Fomes annosus (Fr.) Cooke

Isolates Fa₁ and Fa₂ of Fomes annosus from naturally infected trees of Picea excelsa (P. abies) and Pinus silvestris, in laboratory conditions synthesized the toxic product formannosine. Identification of the fomannosine was by thin-layer chromatography and infra-red spectrophotometry. Maximum production of the toxic metabolite was found in 80-day-old liquid cultures of isolate Fa₂. The isolate Fa₁ synthesized considerably smaller quantities of fomannosine and other components in all ages of culture and media variants.     

A comparison of isolation methods for determining the incidence of Fomes annosus in living loblolly pine1

Several methods were utilized to determine the disease incidence of Fomes annosus (Fr.) Karst. in selected 0.02 hectare plots established in five thinned loblolly pine (Pinus taeda L.) plantations. A total of 79 trees were sampled. Infection as determined by the presence of conks was 2.5 percent. Increment borer samples (two/tree) removed from the root collar zone revealed 10.1 percent infection. Root chip isolations from two, 45 cm long roots per tree indicated 31.6 percent infection. In a random sampling of 10 trees in each of the five plantations, 18 percent infection was found using the two root method. These results indicate that F. annosus may be more prevalent than previously reported.     

Effects of monoterpenes on Fomes annosus (Fr.) Cooke and its phenol oxidase activity

Fomes annosus was cultivated subject to vapours of monoterpenes. Three monoterpenes were tested separately: α-pinene, β-pinene and 3-carene. The terpenes inhibited the dry matter production of the fungus but extracellular phenol oxidase activity was increased, particularly when the fungus was exposed to vapours of β-pinene and 3-carene.     

Fomes annosus Butt-Rot of Sitka Spruce IV. Observations on the Distribution of Cryptosporiopsis abietina (Petrak) in the Stems of Rotted Trees

Cryptosporiopsis abietina was isolated from the heartwood of12 out of 18 Sitka spruce suffering from butt rot caused byFomes annosus, but from none of eight healthy trees from thesame plantations. C. abietina was present in a distinct zoneabove the tissue colonised by F. annosus. It was present inboth sound wood, and in wood with stain or incipient decay. C. abietina inhibited the growth of F. annosus on malt agar,and to a lesser extent in autoclaved Sitka spruce heartwood.The possible influence of this potentially antagonistic funguson infection by F. annosus is briefly discussed.     

Antagonists of Fomes annosus in the rhizosphere of grey alder (Alnus incana) and Norway spruce (Picea abies)

A comparison was made of the fungistatic effects of the root microflora of grey alder and Norway spruce with Fomes annosus as test fungus. The significantly higher frequency of actinomycetes in the alder rhizosphere probably constituted the main difference in this respect. The importance of fungi seemed to be about equal in the rhizosphere of the two tree species. Methods for studies of antagonism are tested and discussed.     

Theoretical modeling of the effects of temperature and moisture content on the acoustic velocity of Pinus resinosa wood

To investigate the effects of temperature and moisture content(MC) on acoustic wave velocity(AWV)in wood,the relationships between wood temperature,MC,and AWV were theoretically analyzed.According to the theoretical propagation characteristics of the acoustic waves in the wood mixture and the differences in velocity among various media(including ice,water,pure wood or oven-dried wood),theoretical relationships of temperature,MC,and AWV were established,assuming that the samples in question were composed of a simple mixture of wood and water or of wood and ice.Using the theoretical model,the phase transition of AWV in green wood near the freezing point(as derived from previous experimental results) was plausibly described.By comparative analysis between theoretical and experimental models for American red pine(Pinus resinosa) samples,it was established that the theoretically predicted AWV values matched the experiment results when the temperature of the wood was below the freezing point of water,with an averageprediction error of 1.66%.The theoretically predicted AWV increased quickly in green wood as temperature decreased and changed suddenly near 0 °C,consistent with the experimental observations.The prediction error of the model was relatively large when the temperature of the wood was above the freezing point,probably due to an overestimation of the effect of the liquid water content on the acoustic velocity and the limited variables of the model.The high correlation between the predicted and measured acoustic velocity values in frozen wood samples revealed the mechanisms of temperature,MC,and water status and how these affected the wood(particularly its acoustic velocity below freezing point of water).This result also verified the reliability of a previous experimental model used to adjust for the effect of temperature during field testing of trees.     

Seasonal differences in freezing stress resistance of needles of Pinus nigra and Pinus resinosa: evaluation of the electrolyte leakage method

Seasonal changes in freezing stress resistance of needles of red pine (Pinus resinosa Ait.) and Austrian pine (Pinus nigra Arnold) trees were measured by an electrolyte leakage method and by visual observation. During most of the year, freezing stress resistance determined by the two methods gave similar results. The electrolyte leakage method provided a good estimate of seasonal changes in freezing stress resistance except for red pine needles in their most winter-hardy state. To obtain a reliable estimate of freezing stress resistance in winter-hardy red pine needles it was necessary to combine the electrolyte leakage method with visual observations. When red pine needles survived exposure to -80 degrees C or lower, electrolyte leakage was never more than 30% even when the needles were exposed to a slow freeze-thaw stress of -196 degrees C. However, rapid freezing of red pine needles to -196 degrees C resulted in electrolyte leakage of over 80%. Red pine needles attained a much higher freezing stress resistance during the winter than Austrian pine. Red pine needles also acclimated and deacclimated faster than Austrian pine needles. An index of injury was developed based on the electrolyte leakage method ((R(2) + R(1))/2, where R(1) is the minimum % electrolyte leakage from noninjured tissue and R(2) is the maximum % electrolyte leakage at the highest injury) that reliably predicted freezing stress resistance of pine needles for most of the year. Important aspects for developing a successful index of injury for pine needles are: use of cut needles, vacuum infiltration and shaking during incubation in water.We conclude that: (1) during cold acclimation the cell wall properties of the pine needles changed and these changes, which appeared to differ in the two species, might explain the very low leakage of electrolytes from winter-hardy needles of red pine; (2) pine needles survive winter by developing the ability to tolerate extracellular ice formation, because after rapid freezing the needles were severely injured; and (3) red pine is adapted to a shorter growing season and colder winters than Austrian pine.     

Effects on seedling development of direct contact of Pinus resinosa seeds or young seedlings with Captan1

Captan, at concentrations up to 2500 ppm did not affect seed germination of Pinus resinosa Ait. However, concentrations of 500 ppm or higher injured roots, stems, and cotyledons within 13 days. Root injury consisted of collapse of root hair cells, epidermal cells, and cortical cells; cotyledon injury of collapse of epidermal and mesophyll cells.     

Effects of 2,3,6-TBA on seed germination,early development,and mortality of Pinus resinosa seedlings1

This study shows extreme phytotoxicity of 2,3,6-trichlorobenzoic acid (2,3,6-TBA) to Pinus resinosa seedlings in the cotyledon stage of development. 2,3,6-TBA caused abnormal seedling development and mortality.     

Genetic variation in Picea abies (L.) Karst. and Fomes annosus (Fr.) Cke. shown by growth of the fungus on wood dust

Growth of Fomes annosus is studied by a test based on growth of previously starved hyphae on sawdust of heartwood of Picea abies as the only nutrition. Our observations show that the method can be used to distinguish beween different spruce individuals or clones, between different Fomes annosus strains and between different growing sites of the trees.     

Inhibitory effect of Trichoderma viride Pers. ex Fr. filtrates on Fomes annosus (Fr.) Cke. In relation to some carbon sources

The mycelial yield of Trichoderma viride on a number of carbon sources and the inhibitory effect of its filtrates on Fomes annosus were investigated. d-Xylose and d-glucose as carbon sources in the media gave the highest degree of inhibition when their filtrates were directly tested against F. annosus mycelium. The protection of pine wood blocks with filtrates was most effective when these were derived from cellulose and d-xylose.